Suspension system for outboard motors



April 9, 1963 E. c. KIEKHAEFER SUSPENSION SYSTEM FOR OUTBOARD MOTORS 2 Sheets-Sheet 1 Filed June 16, 1961 INVENTOR. E LMER C. Kl EKHAEFER .fllllrllj Slur-He Attorneys April 9, 1963 E. c. KIEKHAEFER SUSPENSION SYSTEM FOR OUTBOARD MOTORS 2 Sheets-Sheet 2 Filed June 16, 1961 INVENTOR. ELMER C. KIEKHAEF ER n)z"us E Shit-He Attorneys United States Patent F $384,657 SUEPEN1GN SYSTEM FQR GUTBSARD MOTQRS Elmer Carl Kiekhaefer, Cedarhurg, Wis ass gnor, by mesne assignments, to Kielrhaefer Corporation, 6h:- cago, lib, a corporation of Delaware Filed .lune 16, 19st, er. No. 117,663 11 Claims. (Cl. IRS-1%} This invention relates to an outboard motor and more particularly to a suspension system therefor.

As the size and power of outboard motors are increased, steering control of the motor becomes increasingly difficult because of the larger mass to be controlled. It is generally an object of this invention to provide for improved dirigibility of an outboard motor by means of a suspension which results in a substantial reduction in the mass to be rotationally controlled for steering.

According to the invention, a cowl structure encloses the upper portion of the power unit which comprises a drive shaft housing, an engine supported on the housing and a propeller unit carried at the lower end of the housing. The cowl structure is adapted to support the power unit for rotation on a generally vertical axis relative thereto to provide for steering control of the motor. Bracket means adapted for securement to a boat, support the cowl structure on a transverse horizontal axis to provide for tilting movement of the cowl structure together with the power unit as when the underwater propeller unit strikes an obstruction.

The drawings furnished herewith illustrate the best mode of carrying out the invention as presently contemplated and set forth hereinafter.

In the drawings:

FIG. 1 is a side elevation of an outboard motor which incorporates the suspension of this invention;

FIG. 2 is a front end elevation of the outboard motor of FIG. 1;

FIG. 3 is an enlarged sectional view taken generally on line 3-3 of FIG. 1; and

FIG. 4 is a view similar to that of FIG. 1 with parts broken away and sectioned to more clearly show the outboard motor suspension system of this invention.

Referring to the drawings, the outboard motor is shown mounted on the transom 1 of a boat, not shown, by means of a bracket assembly 2 and includes a power unit 3 which comprises a generally vertical drive shaft housing 4 supporting the engine 5 at the upper end thereof and carrying the propeller unit 6 at the lower end thereof.

The engine shaft, not shown, carries the flywheel 7 at the upper end thereof and is drivingly connected to the downwardly extending drive shaft 8 rotatably supported within the housing 4. The propeller 9 is mounted on a generally horizontal propeller shaft, not shown, which is rotatably supported in the lower unit 6 and is driven by the drive shaft 8 through a suitable gearing arrangement, not shown, interconnecting the propeller shaft and drive shaft to propel the boat.

The engine exhaust accumulated in engine chamber 149 from the cylinders 11 is conducted through the drive shaft housing 4 for discharge beneath the surface of the water through the exhaust snout 12 projecting downwardly from the anti-cavitation plate 13 rearwardly of propeller 9. In the event engine 5 is water-cooled, conduit means for the coolant, not shown, would extend upwardly to the engine within the drive shaft housing 4.

The power unit 3 is rotatably supported within the cowl structure 14 to provide for steering control of the outboard motor. The cowl structure 14 includes an enlarged upper portion 15 which encloses the engine 5 and a narrowing downwardly extending lower portion 16 3,68%,d57 Patented Apr. 9, 1963 enclosing the upper cylindrical portion 17 of the drive shaft housing 4.

A generally horizontal supporting structure 18 is provided within the cowl structure 14 at the location where the cowl portions 15 and 16 merge to form an integral unit. The support 18 includes a cup-shaped depression 19 having an opening 20 therein adapted to receive the upper end of the vertically extending cylindrical portion 17 of the drive shaft housing 4 in spaced relation thereto. The shaft housing 4 is supported within opening 28 by means of the ball bearing 21 which is retained within depression 19 with the outer race of the bearing being seated in an annular right-angle cushion mount 22, of neoprene or the like, disposed in the depression outwardly of the opening. The inner race of bearing 21 is pressed onto the upper end of the shaft housing portion 17 immediately beneath the engine 5 and extends somewhat higher than the outer race to support the engine in spaced relation above the outer race of the bearing.

The lower cowl portion 16 terminates in spaced relation above the non-cylindrical lower portion 2 3 of drive shaft housing 4 and is formed to provide a cup-shaped support 24 having an opening 25 generally vertically aligned with opening 20 of depression 19. A ball bearing 26 is pressed onto the lower end of shaft housing portion 17 and is retained within the cup-shaped support 24 with the outer race of the bearing seated in the annular rightangle cushion mount 27 disposed in support 24 outwardly of opening 25. The vertically spaced bearings 21 and 26 provide for rotation of the power unit 3 relative to the cowl structure 14 on a generally vertical axis whereby to provide steering control for the motor while the cushion mounts 22 and 27 vibrationally isolate the power unit from the cowl structure and bracket assembly 2 and generally lessen the noise level of the motor.

The motor is supported from the transom 1 of a boat by the bracket assembly 2 which includes the C-clamp member 28 fastened to the boat by means of the inboardly disposed clamp screws 29. The clamp member 28 is provided with a pair of opposed arms 30 which respectively extend upwardly and rearwardly along the corresponding sides of cowl structure 14 and terminate in transversely aligned bearing portions 31. A pair of opposed transversely aligned trunnions 32 extend outwardly from the corresponding sides of cowl structure 14 at or near the center of mass of the tiltable motor unit and are journalled in the bearing portions 31 of bracket arms 30 to provide for the pivotal support of the motor unit on a horizontal tilt axis.

The generally vertical or upright operating position of the motor unit is established by a conventional tilt adjustment means including a pair of transversely spaced bracket arms 33 which respectively extend rearwardly from clamp member 28 on the corresponding sides of cowl structure 14. The bracket arms 33 are provided with a plurality of spaced openings 34 which are transversely aligned between the respective arms. A tilt adjustment bar 35 is selectively disposed in aligned openings 34 of the spaced arms 33 and is engaged by the front of cowl structure 14- in the normal upright operating position of the motor unit.

Means such as one or more shock absorbers 36 are disposed between the clamp member 28 and cowl structure 14 to dissipate the angular momentum of the motor unit as may be imparted thereto when the propeller unit 6 strikes an obstruction. As shown in the drawings the corresponding ends of each shock absorber 36 are pivotally mounted on transversely extending pins 37 and 38 provided respectively on clamp member 28 and cowl structure 14.

Rotation of power unit 3 within the cowl structure 14 on a generally vertical axis may be variously effected to provide for steering control of the outboard motor. According to the embodiment shown in the drawings, and referring particularly to FIG. 3, steering control for the power unit 3 is provided by a closed hydraulic system 39 wherein the fluid is displaced between opposing steering cylinders 4i and ll by a master cylinder 42. Steering cylinders 49 and 41 are disposed within cowl structure 14 and are pivotally secured on vertical pins 43 provided in generally transversely aligned relation on the respec tive sides of the cow]. The corresponding rods 44 and 45 of the cylinder pistons are respectively pivotally connected on vertical pin 46 provided on engine 5. The corresponding cylinders 46 and 41 are hydraulically connected through flexible pressure lines 47 and 413, respectively, to the respective ends of the remotely disposed master cyl inder 42. The hydraulic fluid is displaced between the opposing cylinders 40 and 41 to effect steering control of the outboard motor by movement of the piston 49 in the master cylinder 42. As shown in FIG. 3, selective movernent of piston 49 within master cylinder 42 may be accomplished by a manually operable steering wheel 50 whereby the gear 51 is rotated. Gear 51 is disposed in operative engagement with the rack portion 52 formed on rod 53 of piston 49. Thus, selective rotation of the steering wheel 50 provides the necessary steering control of power unit 3 within the cowl structure 14. It will be noted that the closed hydraulic system providing for steering movements of the power unit requires no valving and is not disturbed when the motor unit tilts about its transverse horizontal axis.

Since only the power unit 3 of the described improved outboard mOtOr suspension is rotated for steering control of the motor, the inventionprovides for improved steering over conventional suspensions in that a lesser mass need be controlled. The invention further provides for separation of-the cowl structure 14 from the power unit 3 by means of cushion mounts 22 and 27 whereby engine vibration and the attendant noises are isolated from the cowl structure. The improved suspension also provides for support of the motor unit at or near the center a of mass thereof to produce a balanced mounting with respect to the bracket assembly 2 to greatly reduce shocks and stresses on the boat transom.

Various modes of carrying out the invention are contemplated as being within the scope of the following claims particularly pointing out and distinctly claiming the subject matter which is regarded as the invention.

I claim:

1. In a dirigible outboard motor, a power unit adapted to drive a boat, a cowl structure enclosing the upper portion of the power unit and adapted to support the power unit for rotation on a generally vertical axis relative to the cowl structure to provide for steering control of the motor, and bracket means "adapted for securement to a boat, said cowl structure being carried by said bracket means on a transverse horizontal aXis to provide for tilting movement of the power unit in a generally vertical plane as when the lower end of the power unit strikes an obstruction.

2. The invention of claim 1 wherein the transverse horizontal tilt aXis is disposed substantially at the center of mass of the combined power unit and cowl structure.

3. In a dirigible outboard motor, a power unit adapted to drive a boat, a cowl structure enclosing the upper portion of the power unit and being spaced therefrom, hearing means carried by the cowl structure and adapted to rotatably support the power unit to provide for steering control of the motor, means to etfect rotation of the power unit within said bearing means, and bracket means adapted for securement to a boat, said cowl structure being carried by said bracket means on a transverse horizontal aXis to provide for tilting movement of the power unit in a generally vertical plane as when the lower end of the power unit strikes an obstruction.

4. The invention of claim 3 wherein the bearing means 4i, for rotatably supporting the power unit comprises vertically spaced and aligned ball bearing units retained by the cowl structure.

5. The invention of claim 3 wherein the cowl structure includes vertically spaced generally horizontal internal support means adapted to retain said bearing means.

6. The invention of claim 3 wherein the cowl structure includes vertically spaced generally horizontal internal support means adapted to retain said bearing means, and resilient cushioning means interposed between said support means and bearing means to vibrationally isolate the cowl structure from the power unit.

7. In a dirigible outboard motor; a power unit comprising a drive shaft housing, an engine supported at the upper end of said drive shaft housing and a propeller unit carried at the lower end of said housing; a cowl structure enclosing the upper portion of the power unit and having vertically spaced generally horizontal internal support means provided with aligned openings through which said drive shaft housing extends; bearing means disposed on the drive shaft housing and carried by the internal support means of the cowl structure to rotatably support the power unit for steering control of the motor relative to the cowl structure; means to effect rotation of the power unit within cowl structure; resilient cushioning means interposed between said support means and bearing means; and bracket means adapted for securement to a boat; said cowl structure being carried by said bracket means on a transverse horizontal axis to provide for tilting movement of the power unit in a generally vertical plane as when the propeller unit strikes an obstruction.

8. In a dirigible outboard motor; a power unit comprising a drive shaft housing having an upper cylindrical portion, an engine supported at the upper end of the cylindrical housing portion and a propeller unit carried at the lower end or" said housing; spaced bearing means disposed on and adjacent the respective ends of the cylindrical portion of said drive shaft housing; a cowl structure enclosing said engine and the cylindrical housing portion of the power unit and having vertically spaced and gen.- erally horizontal bearing retainer means provided with vertically aligned openings; said cylindrical housing portion extending through said openings and the respective bearing means being disposed in the corresponding retainer means to support the power unit for rotation relative to the cowl structure and for steering control of the motor; means to effect rotation of the power unit within the cowl structure; resilient cushioning means interposed between the bearing means and the retainer means therefor; and bracket means adapted for securement to a boat; said cowl structure being carried by said bracket means on a transverse horizontal axis to provide for tilting movement of the power unit and cowl structure in a generally vertical plane as when the propeller unit strikes an obstruction.

9. The invention of claim 8 wherein the transverse horizontal tilt axis is disposed substantially at the center of mass of the combined power unit and cowl structure.

10. The invention of claim 8 wherein the bearing means for rotatably supporting the power unit comprise ball bearing units.

11. In a dirigible outboard motor; a power unit comprising a drive shaft housing having an upper cylindrical portion, an engine supported at the upper end of the cylindrical housing portion and a propeller unit carried at the lower end of said housing; spaced ball bearing units disposed on the cylindrical portion of said drive shaft housing with the upper of said units being adjacent to the engine and the lower of said units being adjacent the lower end of said cylindrical portion; a cowl structure enclosing the engine and the cylindrical housing portion of the power unit with the lower portion of the cowl structure enclosing the cylindrical housing portion tapering downwardly and terminating in a cup-shaped bearing retainer corresponding to the lower bearing unit sesame? 5 on the drive shaft housing; support means within the cowl structure and provided with a cup-shaped bearing retainer corresponding to the upper bearing unit on the drive shaft housing; the respective bean'ng retainers of said cowl structure having vertically aligned openings through which the cylindrical portion of the drive shaft housing extends with radial clearance and the respective bearing units being seated in the corresponding retainers to support the power unit for rotation relative to the cowl structure and for steering control of the motor; means to effect rotation of the power unit within the cowl structure; an annular resilient cushion element interposed between the respective retainers and the corresponding bearing unit to vibrationally isolate the cowl structure from the power unit; and bracket means adapted for securement to a boat; said cowl structure being carried by said bracket means on a transverse horizontal axis disposed substantially at the center of mass of the combined power unit and cowl structure to provide for tilting movement of the power unit and cowl structure in a generally vertical plane as when the propeller unit strikes an obstruction.

References Cited in the file of this patent UNITED STATES PATENTS 1,555,017 Lind Sept. 29, 1925 2,723,639 Hinrichs Nov. 15, 1955 2,74(),368 Irgens Apr. 3, 1956 2,953,335 Kiekhaefer Sept. 20, 1960 

1. IN A DIRIGIBLE OUTBOARD MOTOR, A POWER UNIT ADAPTED TO DRIVE A BOAT, A COWL STRUCTURE ENCLOSING THE UPPER PORTION OF THE POWER UNIT AND ADAPTED TO SUPPORT THE POWER UNIT FOR ROTATION ON A GENERALLY VERTICAL AXIS RELATIVE TO THE COWL STRUCTURE TO PROVIDE FOR STEERING CONTROL OF THE MOTOR, AND BRACKET MEANS ADAPTED FOR SECUREMENT TO A BOAT, SAID COWL STRUCTURE BEING CARRIED BY SAID BRACKET MEANS ON A TRANSVERSE HORIZONTAL AXIS TO PROVIDE FOR TILTING MOVEMENT OF THE POWER UNIT IN A GENERALLY VERTICAL PLANE AS WHEN THE LOWER END OF THE POWER UNIT STRIKES AN OBSTRUCTION. 